Electron-discharge apparatus.



'I.1LANGMU|R.

I ELECTRUN DISCHARGE APPARATUS. APPucATloN man OCT. 1.6. '1913.' -maNEwgD MAR.1'4. 191s,

Patented July 25x/1918*- u rm fu "I7 .nl 2 7 -imm .VT i ...IM 2

Inventor Irving Larjgmuir Witnesses ravine mammie, or scHEnEcranr, NEW Yoan, Assienoa ro .GENEnAL ELECTRIC j company, a conronarmiv or NEW Yonx.

Emerson-DISCHARGE ArrAnA'rUs.

HEISSUED Application -led October 16, 1913, Serial No. 795,609. Renewed Marchi 14, 1918. Serial No. 84,241.

To all whom it may concern.

Be it known that I, IRviNG LANGMU'IR, a citizen of the United States, residing at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Electrn- Discharge Apparatus, of which the following isa specification.

The present invention relates to electron discharge devices, tubes having an incandescent cathode.

Devices of this nature as described and broadly claimed in a copending application,

Serial No.i795,610, led October 16, 1913,

are provided with an electron-emitting cathode, an anode, and a conducting body, commonly termed a grid, consisting ordinarily of an electrical conductor located betweenl cathode and anode for statically controlling the electrical discharge conditions of the tube. Electron discharge devices as described in the above application may be operated at exceedingly high voltages and have a high load capacity. This new apparatus is suited for use in a much wider iield than former devices of this nature which were limited lto low voltages and very feeble curor example, discharge' The present invention, comprises various structural features of novelty which Ycoperate to increase the range and capacity of a device of this type.` For example, in accordance with my invention the grid is supported on a supporting frame-work in such manner that mechanical displacement of the grid by stat-ic strains or by mechanical. shocks cannot easily occur.- Other features of novelty are. pointed out with particularity in the claims.

In' the accompanying drawings" various forms of apparatus are shown illustrative of my invention. Fi ure l illustrates an electron ,discharge tube with its parts assembled, and

Figs. 2 to 5 inclusive, show alternative forms of electrode and idconstructions.

As shown in Fig. 1, the various parts of the apparatus may be mounted in an inclosing envelop or globe 1 upon a lpedestal 2 similar to the mount employed for incandescent lamps. The cathode construction is shown in Fig. 2.v It consists of a substantially straight filament 4 consisting of highly l refractory material, preferably tungsten,

and provided with terminals 5, 5. The fila-r ment -4 is mounted, preferably attached to a .light spring 6, between' two oppositely discases may to 4advantage consist of metal. 60

Upon this frame-work is wound a Wire 9, which has such a small diameter or section that it is too yieldin to retain Without the aid of the framewor a' desired position or configuration. The turns of conductor are.

closely adjacent to each other and are also very closely adjacent to but are out of contact with the incandescent cathode.- The conductor 9, which may be very ine and eX- tends in the forms illustrated transversely '10 across the space between the cathode and the anode, constitutes a grid which by means of applied potential exerts lan electrostatic control upon the electron discharge.

The supporting frame-work for the cathode and grid is attached to a rod 10, mounted upon the stem of thel tube. Adjacent to the cathode and gridis the anode 11 which in the present case has been indicated as con- -sistingBof a wire strung in a -zig-zag manner over hooks 12 upon fork-shaped supports 13 and 14 but it is not necessary that it should assume this particular form..A As indicated, the anode also may consist. of a conductor or wire which has such small section that `it is not self-supporting and, therefore, is carried upon a framework which is upheld by the support which carries the grid framework, and as will be described in connection with Fig. 4, the second framework may be placedL upon the first-mentioned framework carry-l ing the grid conductor. Both anode and grid referably consist of tungsten, but other gasree refractory metals may be used.. By a constituting the anode a continuous conduc- '95 tor -it` can be conveniently heated by passage of current during evacuation of the device and for' this purpose is attached to leadin in conductors 15, 15. The cathode termina s 5, 5 are supplied with current through lead- 100 ing-in wires' 16,16. Although it is not necessary for all purposes to provide cpn-` i nections for each end of the grid it is desirable Jto do so when the potential applied to 'the or -iiiear cathode the potential gradient along the grid may to advantage be the same as that on the lament. In this manner the potential drop from grid to cathode is the Asame along its length. The grid indicated 110 cartier.

Patented .filly 23, 191e.

id is small and in the case of a straight in Fig. 1 as being attached to leading-in conductors 17, 17 at opposite ends.

In some casesit is desirable to use a V- shaped incandescing conductor for the cathode and to attach to its b ight a spring as' shown at 18, 19 in Fig. 3. In this manner Contact of the conductor with the grid by sagging when the Ametal is expanded at high temperature is prevented. In Fig. 3 a plurality of loops are lused in order to increase the amount of cathode surface. The' filaments are connected in parallel by means of conductors 20, 20. I

In Fig. 4 the cathode 4 has beenN shown as being moun ed in a frame 21, consisting of ferrochronie, tungsten, or j other suitable metal upon which the wire 22 constituting the grid is Wound. As the grid Wire is thus wound upon a conductive frame its turns.

are in parallel and electrical contact may be made directly to the frame 21 by conductor 23. The leading-in conductors 5, 6 for the cathode are insulated from the frame by glass supports 24 as indicated.

Upon the frame 21 are placed mica sheets 25 and 26 which serve to insulate the wire 27 constituting the anode from the grid. The leading-in conductors 28, 28 to' which the ends of the wires are anchored may be attached to glass beads 29 fused upon the frame 21.

In Fig.A 5 not only the grid 32 is wound upon the frame 33 but' also the cathode wirev 34 is wound'upon stout metallic conductors 35, 36, consisting preferably of tungsten. The conductors- 35, 36 areattached respectively to an anchoring wire 37 and to twov springs 38 and 39 serving to hold taut the turns of the tungsten wire constituting the cathode and to prevent them from coming into contact with the grid wire 32. A stranded copper conductor 40 may be used to conductA current to the cathode.

In preparing the apparatus, the preliminary exhaust is carried out by the most ivm-` proved methods such as Cused in incandescent lamp manufacture. then subjected to an electron discharge or bombardmentby impressing a suitable voltage between the cathode and anode. When the anode consists of a conductor such as wire 11, Fig. 1, it is preferably heated 4by passage of current either before or during the bombardment. When the anode is plateshaped the heating may form part of the treatmentby electron bombardment, the discharge current being made heavy enough to heat the anode, but heating is not essential. The removal of the gas from the anode is not due to heat alone, but is due to electrical effect. The voltage should be so chosen at the beginning of the electron discharge treatvment that blue glow is absent in the tube as this indicates that ionization of the residual gas by collision of gas molecules with The anodes are voltage is higher than the voltage at which the device is normally .operated but this rule will not hold true when the operating 'voltage is very high as substantially all the gas may be removed before the operating voltage is exceeded. Evacuation of the device should preferably be carried to a pressure as low as a few hundredths of a micron o-r even lower although no definite limits may be assigned.` In any event evacuation should be so low that no appreciable gas ionization takes place during normal operation. When the cathode and anode are very close together and the discharge is confined to a directpath, a greater gas pressure is permissible dthan when the opposite is true.

An electron discharge tube may bev used in various electrical systems, for example,

as in receiving systems for radio-telegraphy.'

The passage of electron current across the evacuated Aspace between cathode and anode is controlled by the potentials impressed upon the grid. A tube prepared as above described may be used to transmit currents limited in potential only by the dielectric strength of the glass; quartz or other material of the tube and the mechanical strength of parts subjected to static forces. y

What I claim as new and desire to secure by Letters Patent of the United States, is

1. electrical vacuum discharge apparatu's-comprising a highly evacuated envelop, a cathode adapted to be heated, a coperating anode, a rigid framework, an unheated conductor, constituting a grid, wound back and forth on said frame-work with closely adjacent turns and located'between cathode and anode, and external connections for said electrodes and said grid.

-2. The combination of a highly evacuated envelop, a cathode, a coperating anode, rods spaced apart and adjacent said cathode, a grid conductor having too small a diameter to be self-supporting wound over said rods withmlosely adjacent turns and having a plurality of sections transverse to said rods, Iand external connections for said electrodes and said grid.

3. An electron vdischarge apparatus comprising an evacuated envelop, an electronemitting cathode, a coperatin'g anode, a frame-work spaced about said cathode, and a conductor wound. about said framework closely adjacent said cathode.

4. An electron discharge apparatus comergy to incandesce said conductor, bars l0- cated on opposite sides of said conductor,` a wire wound with closely ad'acent turns" on said bars to constitute a gri but out of contact with said incandescing conductor, a

set but insulated therefrom and a conductor constituting an anode mounted thereon in a plane substantially parallel to saidgrid,'a nd leading-ini conductors toz said grid and anode.

5. A vacuum discharge tubeecomprising a highly evacuated envelop, a cathode adapted to be heated, a coperating anode, a framework located adjacent thereto, a conductor mounted thereon, and having" turns inclos# ing said cathode, and external connections for said electrodes and -said conductor.. 6.7Th'e combination of a gas-tight highly evacuated envelop, a lamentary conductor adapted to be heated, constituting a cathode, a frame consisting of conductive material spaced about said' conductor, a conductor 5 0 pendently emit electrons, a supporting framef work vcarried there electrons, supporting'bars located' ono po` wound on said frame with closely adjacent turns surrounding said cathode and consti-V tuting a grid., Ainsulating supports adjacent said grid, a second gconductor constituting an anode wound uponsaid supports,'and eX- ternal current. connections for said electrodes and grid.

7. An electrical device comprising the combination fof' an inclosing envelop, a cathode, means for causing said cathode to .emit electrons, an anode, a selfsupporting framework located between said electrodes,

and an electrical conductor mounted on said f framework and extendin transversely the direct path between said electrodes.

8. An electrical apparatus comprising the combination of a cathode adapted to emit electrons independently of the current, an anode, a supporting framework, a wire mounted on said framework, said wireV having too small a cross-section tobe selfsupporting, constituting a charge-receiving grid, an inclosing 'evacuated envelop, and eleetrical -connections for said electrodes and. gfl

9. Anelectrical apparatus comprisin the combination of a cathode, adapted tiindework, a conductor having too small a section to be self-supporting molmtedfthereon, a second framework adjacent the first, a Vsec? ond conductor mounted on said second framework insulated from. said first-named conductor, an inclosing envelop, andl external connections for said elements.

10. An electrical apparatus comprising theu combination of a cathode adapted to lemit site sides of said cathode, a wire woun on `said bars to constitute a grid, a second set of self-supporting bars adjacent said first set but insulated therefrom, 'a' second .wi-re" wound on said second set. of bars, constitutternal electrical connections forv said cathode,

grid and anode.

i 11. An electrical apparatus comprising-'the 5 second set of bars closely ad] acent to the first comblnation o f an evacuated envelop, a supporting framework therein, a cathode mounted on said framework, an unheated conrio ductor positioned to control an electrical' discharge emitted by said cathode and extending transversely to a directl path between. fsaid cathodeand anode, said conductor being also mountedon said framework, and a icooperating anode within said envelop.

12. An electrical apparatus comprising the combination of an evacuated vgas-tight envelop, a supporting framework therein, a

cathode carried by4 said framework, a dis' y'charg'e-controlling conductor'also carried by said framework and surrounding said catho'de'an'd a coperating anode within said envelop.

13. An electrical. device comprising the combination ofa supporting stehn'framework carried thereby, a ila'mentary cathode ,of refractory material supported by saidv framework, a discharge-controlling conductor having toosmall a section to be self-supi porting wound onsaid framework about and.

ose proximity to said cathode, a second L in cl framework alsocarried by said stem, an

anode supported by said second framework,

an inclosing evacuated envelop, and electrical leading-in conductors, joined respec-` i porting framework therein,a cathode mounted on said framework adaptedto'be' operated operating at incandescence, a discharge-controllin conductor alsomounted on said framewor and extending transversely across the tdirect path between saidcathode and anode, `said conductor being of such smallcross-section as to be unable to maintain a; desired con' figuration vwithoutthe framework, and a co-A operating anode.

15, An electrical device comprisingthe combination of a su porting stem, aframey, a cathode mounted `on`"'said' framework, a discharge-controlling conductor also mounted'on said framework a second framework also carried by said l 'stem,an anode supported by said `second` framework, an inclosing evacuated 'enve'l( p,

and electrical leading-1n conductors sealed ductor "andl said anode.

materiaal, discharge-controlling.conductor, both said/cathode and conductor being caeried 'IW/said framework land having such` 16., An electrical device comprising the' combination 'of aA supporting stem, a frame- 1" work upheld thereby, a cathode of refractory in sasid envelop and joinedrespectively to V said cathode, said ldischarge-czmtrolling consmall section as to be too yielding tobe selfsupporting, ried by said stem,

I charge-controlling conductor and said anode.

17. An electrical device comprising the combination of a `framework, a filamentary cathode of tungsten supported by said framework, a tungsten wire wound with closely adjacent turns on said framework constituting a discharge controlling grid, a second framework closely adjacent the first framework, a second tungsten wire mounted on said second framework but out of electrical contact with the cathode and grid, a common support for both frameworks, an inclosingenvelop evacuated to such lowfpressure that conduction of energy can occur therein substantially independently of positive gas ionization, and electrical leading-in conductors sealed into said envelop and connected 'respectively to saidcathode, said grid and said anode.

18. An electrical device comprising the combination of a cathode, an anode, a framework having a plurality of arms spaced apart, a discharge-controlling conductor eb tending from one of said' arms to another arm, transverse to a direct path between said cathode and anode, an inclosing envelop, and external connections for said electrodes and said conductor.

19. An electrical device -comprising the combination of a refractory cathode, an anode, means for heating said cathode independently of a discharge between said cathode and anode, a framework located between said electrodes and an unheated con- -ductor mounted on said framework and surrounding one of said electrodes, and an inclosing envelop into which electrodes and said unheated conductor are sealed.

20. An evacuated envelop containing three electrodes one of which is a filament adapted to be heated, another a charge receiving anode, a self-supporting framework spaced about one of said electrodes, and a third electrode consisting of a wire mounted on said framework and located transversely to the space between said electrodes.A

In witness whereof, I have hereunto set my hand this 15th day of-October, 1913.

IRVING LANGMUIR. Witnesses:

BENJAMIN B. HULL, `W. G. GARTNER. 

